"Wigmore’s technique, like probability itself, is both wide-ranging and tediously painstaking; his book was popular only among insomniac judges. But now that computers can take on the numerical drudgery, it is proving its worth in just such tangled cases as Sacco’s and Vanzetti’s. The legal scholars Joseph Kadane and David Schum have applied a sophisticated extension of Wigmore’s method to the vast body of evidence from the case. Theirs is a remarkable achievement; their charts retain all the original complexities: the facts withheld or perverted, the hearsay, the lies told and disavowed on both sides, the charged political atmosphere of eighty years ago. They never discount a fact, no matter how far-fetched; they  simply give it its due weight in their dynamic structure.

Their conclusion?  Unjust though it is to summarize a book in a sentence, the balance of probability seems to favor the view expressed long ago by one of the defendants’ close companions: “everyone in the Boston anarchistic circle knew that Sacco was guilty and that Vanzetti was innocent as far as the actual participation in the killing.” So, there it is: whichever side our political instincts favor, we are destined to be half wrong.

Vanzetti’s last words were: "I wish to forgive some people for what they are now doing to me."  If we were all willing to make the extra effort to work out the probabilities, perhaps we might not need forgiveness so often."